Simple and highly Z-selective ruthenium-based olefin metathesis catalyst.

Area of Science:

• Organometallic Chemistry
• Catalysis
• Organic Synthesis

Background:

• Olefin metathesis is a powerful tool for C=C bond formation.
• Grubbs-Hoveyda second-generation catalysts are widely used but often lack high Z selectivity.
• Developing catalysts with improved stereoselectivity is crucial for targeted synthesis.

Purpose of the Study:

• To synthesize and characterize a new Grubbs-Hoveyda catalyst variant.
• To evaluate the catalytic activity and Z selectivity of the novel catalyst in olefin metathesis.
• To compare the performance and properties of the new catalyst with its parent compound.

Main Methods:

• One-step substitution of chloride ligand in Grubbs-Hoveyda second-generation catalyst.
• Synthesis of 2,4,6-triphenylbenzenethiolate ligand.
• Olefin metathesis reactions, including homocoupling of terminal olefins.
• Analysis of Z selectivity and turnover numbers.

Main Results:

• A novel catalyst was successfully synthesized by replacing a chloride anion with a 2,4,6-triphenylbenzenethiolate ligand.
• The new catalyst exhibited remarkable Z selectivity, achieving up to 96% in homocoupling of terminal olefins.
• High turnover numbers (up to 2000) and sustained Z selectivity (>85%) were observed.
• The catalyst demonstrated robustness towards oxygen and water, similar to the parent catalyst.

Conclusions:

• The novel Grubbs-Hoveyda catalyst with a triphenylbenzenethiolate ligand is highly effective for Z-selective olefin metathesis.
• This catalyst offers a valuable alternative for synthesizing Z-olefins with high efficiency and selectivity.
• Its robustness and performance characteristics make it suitable for various synthetic applications.